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Micro and nanolattice fabrication using projection micro litho stereo exposure additive manufacturing techniques and synchrotron X-ray 3D imaging-based defect characterization

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science China(Technological sciences) 2020年第4期63卷 561-570页

作者： HU WenXia LIU LiWu WU WenWang XI Li LENG JinSong FANG DaiNing Institute of Advanced Structure Technology Beijing Institute of TechnologyBeijing 100081China Department of Astronautical Science and Mechanics Harbin Institute of TechnologyHarbin 150001China National Key Laboratory of Science and Technology on Advanced Composites in Special Environments Harbin Institute of Technology(HIT)Harbin 150080China Department of Mechanical Engineering Massachusetts Institute of TechnologyCambridge MA 02139USA

Synchrotron radiation X-ray micro-computed tomography(SR-μCT)is a 3D imaging technique that is widely employed for the characterization of defects in advanced materials and *** this study,we characterize several typical defects in octettruss and re-entrant 3D lattice structures by using SR-μ*** 3D micro-lattice structures are manufactured using projection micro litho stereo exposure(PμLSE)additive manufacturing *** as-fabricated 3D lattice samples are characterized using optical microscopy,and subsequently,by SR-μ*** more,a statistical analysis is performed to characterize the surface roughness and internal defects qualitatively,whereby the statistical geometrical parameters of struts along different directions and strut joints are analyzed and ***,several typical defects are identified:(1)holes at the joints of the strut and irregular diameter deviations of the strut in the octet-truss lattice structure;(2)irregular diameter variations,bulges,dislocations,grooves,accumulations,and torsion in the re-entrant lattice *** of these defects are related to the building direction,the weight of the structure,bubbles,dust,and impurities during the PμLSE additive manufacturing process.

关键词： synchrotron radiation X-ray additive manufacturing lattice structures defect characterization

Cohesive Contact Insight to Stick-Slip Mechanism of Flexible Film/Substrate Bilayer Structure

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SSRN 2024年

作者： Liu, Shouyao Wu, Jian He, Shixue Yuan, Xuebo Stupkiewicz, Stanislaw Wang, Youshan National Key Laboratory of Science and Technology on Advanced Composites in Special Environments Harbin Institute of Technology Harbin150001 China Center for Rubber Composite Materials and Structures Harbin Institute of Technology Weihai264209 China Institute of Fundamental Technological Research Polish Academy of Sciences Warsaw02-106 Poland Applied Mechanics and Structure Safety Key Laboratory of Sichuan Province Southwest Jiaotong University Chengdu610031 China

As the critical feature of the stick-slip for soft materials, the interfacial Schallmach waves of flexible composite structures are essential for smart tactile sensors to realize sliding perception. Herein, the stick-slip mechanisms of Polydimethylsiloxane film/substrate bilayer structures (PF/SBS) with three substrate stiffnesses regulated by porosities are investigated using in-situ testing and cohesive contact modeling methods. The microcontact stiffness inhomogeneity disrupts the continuity and synchronization of Schallmach waves and causes non-periodic fluctuations in contact force. The buckling phenomenon of the film structure marks the transition from stick to slip. During the Schallmach wave propagation, the mode mixity angle located at the left shoulder varies between 0° to 27°, and the rear of the contact zone varies between 0° to 2.8°. © 2024, The Authors. All rights reserved.

关键词： Stick-slip

4D printed shape memory polymers and their structures for biomedical applications

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science China(Technological sciences) 2020年第4期63卷 545-560页

作者： LI YueJia ZHANG FengHua LIU YanJu LENG JinSong National Key Laboratory of Science and Technology on Advanced Composites in Special Environment Harbin Institute of Technology(HIT)Harbin 150080China Department of Astronautical Science and Mechanics Harbin Institute of Technology(HIT)Harbin 150001China

Shape memory polymers are smart materials that produce shape changes under external stimulus ***-dimensional(4D)printing is a comprehensive technology originate from deformable materials and three-dimensional(3D)printing *** present,4D printed shape memory polymers and shape-changing structures have been applied in various fields,especially in the field of biomedical science.4D printing technology has made a breakthrough of personalized customization in the traditional medical field,providing a new direction for the further development of the biomedical *** this review,the recent research and development of shape memory polymer,3D printing technology,4D printed shape memory polymers and shape-changing structures in biomedical area are *** examples and applications of 4D printed shape memory polymers and their structures in the area of biomedical are also *** on 4D printing,stimulated by different conditions,3D printed objects can be fabricated into various biomedical applications such as cell scaffolds,vascular stents,bone scaffolds,tracheal stents and cardiac stents by different 3D printing ***,the application prospects,existing technical restriction and future development directions of 4D printed shape memory polymers and their structures in the biomedical field are summarized.

关键词： 4D printing shape memory polymers shape-changing structures biomedical applications

Anomalous thermal response of bulk diamond to uniaxial (100) strain: A first-principles prediction

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Physical Review B 2022年第18期106卷 184303-184303页

作者： Biao Wang Jiwen Zhao Yanwei Hu Yurong He Nikolay Rodionov Jiecai Han Jiaqi Zhu National Key Laboratory of Science and Technology on Advanced Composites in Special Environments Harbin Institute of Technology Harbin 150080 China School of Energy Science & Engineering Harbin Institute of Technology Harbin 150001 China State Research Center of Russian Federation Troitsk Institute for Innovative and Fusion Research Troitsk Moscow 108840 Russia Key Laboratory of Micro-systems and Micro-structures Manufacturing Ministry of Education Harbin 150080 China

Diamond, a material that exhibits ultrahigh thermal conductivity with a sensitive thermal response to stress, is an ideal heat-sink material in the embedded cooling paradigm. This study uses first-principles calculations with the phonon Boltzmann transport equation to predict the variation rules of the thermal conductivity of diamond along the 〈100〉 crystal direction under strains at three orders of magnitude: 0.1%, 1%, and 10.5%. Density functional theory is used to predict the stress–strain dependence of diamond and the temperature-dependent thermal conductivity of unstrained diamond. The predictions are in good agreement with the experimental results. The calculated uniaxial strain–thermal conductivity dependence results reveal that the thermal conductivity of diamond abnormally increases by approximately 15% under small-scale uniaxial strain because of the weakened anharmonic interatomic force constants. Under large-scale strain, the thermal conductivity considerably decreases because of reduced phonon group velocities and increased numbers of phonon scattering channels. The findings in this study will guide analyses of the dependence of thermal conductivity on strain in other diamondlike structures, such as Group IV element-based materials. The abnormal thermal response at small strain is expected to lead to the realization of an artificial thermal conduction channel.

关键词： Thermal conductivity Diamond Boltzmann theory Density functional theory

Conjugated Bond-Based Peridynamic Model of Laminated Composite Materials with Arbitrary Poisson's Ratio and Shear Modulus

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SSRN 2023年

作者： Liu, Shuo Che, Lu Fang, Guodong Liang, Jun Institute of Advanced Structure Technology Beijing Institute of Technology Beijing100081 China School of Civil Aviation Northwestern Polytechnical University Xi’an710072 China Yangtze River Delta Research Institute of NPU Taicang215400 China Science and Technology on Advanced Composites in Special Environments Key Laboratory Harbin Institute of Technology Harbin150001 China

The bond-based peridynamic (BB-PD) theory is inadequate in describing the four independent engineering material constants of composite lamina, which results in fixed values its Poisson’s ratios and shear moduli. This study presents a novel lamina conjugated BB-PD model encompasses not only the fiber bond and matrix bond, but also the transverse bond and conjugated bond pair. By defining these four basic PD bonds, the improved conjugated BB-PD model can overcome the restriction of material properties. The determination of the four basic PD micro-modulus parameters is achieved through the utilization of the equivalent relationship of strain energy density. In addition, the lamina conjugated BB-PD model is extended to deal with composite laminates with different stacking sequences. The present study validates the accuracy and applicability of the conjugated BB-PD model for composite materials by conducting simulations of the elastic deformation and progressive damage behavior of unidirectional laminae and laminates. Moreover, the proposed model provides an elucidation of the damage modes and failure mechanisms of laminated composite materials subjected to uniaxial loading. © 2023, The Authors. All rights reserved.

关键词： Elastic moduli

Effects of Non-Uniform Needled Microstructure on Failure Mechanisms of 3d Needled C/C-Zrc-Sic composites Thick-Walled Cylinder Under Axial Compression and Internal Pressure

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SSRN 2022年

作者： Wang, Zhangwen Wang, Bing Jiang, Xinyu Wang, Xiaosong Sun, Wei Fang, Guodong Meng, Songhe Science and Technology on Advanced Composites in Special Environments Key Laboratory Harbin Institute of Technology Harbin150001 China National Key Laboratory of Precision Hot Processing of Metals Harbin Institute of Technology Harbin150001 China State Key Laboratory of Powder Metallurgy Central South University Changsha410083 China

Three dimensional (3D) needled ZrC-SiC modified C/C composites (C/C-ZrC-SiC composites) as cutting-edge materials for throat or expansion section of rocket nozzle are mainly subjected to complex loads conditions of internal pressure and axial force. The coupled axial compression and internal pressure experiments of 3D needled C/C-ZrC-SiC composites thick-walled cylinder were carried out to study the damage modes and failure mechanisms combing with the optical microscope and micro computed tomography (Micro-CT). A meso-macro finite element (FE) model considering local needling fiber regions was also established to investigate the failure process of the thick-walled cylinder under the complex loads. The predicted strength, failure strain and ultimate crack morphologies obtained by the proposed model were in good agreement with the experimental results. The effect of needled region distribution on the crack evolution and damage mechanisms was further analyzed. The non-uniform distribution of needled fiber region can induce the stress concentration of no needled regions under circumferential tension, which can trigger crack initiation and deflection. This study can be helpful of establishing the relationship between the structural behavior of ultra-high temperature ceramics modified C/C composites nozzle and the 3D needled composites design. © 2022, The Authors. All rights reserved.

关键词： Finite element method

Power Law Analysis of Thermal Conductivity of Bulk Diamond Under Isotropic and Uniaxial (100) Strains: First-Principles Predictions

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SSRN 2023年

作者： Wang, Biao He, Yurong Rodionov, Nikolay Zhu, Jiaqi National Key Laboratory of Science and Technology on Advanced Composites in Special Environments Harbin Institute of Technology Harbin150080 China School of Energy Science and Engineering Harbin Institute of Technology Harbin150001 China State Research Center of Russian Federation Troitsk Institute for Innovation and Fusion Research Troitsk Moscow108840 Russia Key Laboratory of Micro-systems and Micro-structures Manufacturing Ministry of Education Harbin150080 China

The miniaturization of high-frequency electronic devices is associated with significant heat accumulation by individual components. Diamond exhibits ultrahigh thermal conductivity and is thus an ideal material for heat dissipation. Considering the sensitive stress-thermal responses of diamond, this study uses first-principles calculations and the phonon Boltzmann transport equation to compare and analyze the effects of uniaxial strain along the crystal direction, as well as isotropic strain, on the thermal conductivity of bulk diamond. Under isotropic strain, the thermal conductivity is principally influenced by bond length;the relationship between thermal conductivity and the bond length deformation index follows a power law. During uniaxial strain, the bond angle and bond length change simultaneously, superimposing their effects on thermal conductivity. This study provides essential insights into the mechanisms of diamond thermal conductivity under different strains;the findings can guide prediction of the strain-thermal conductivity relationships of other crystalline materials. © 2023, The Authors. All rights reserved.

关键词： Strain

Crystallization Modulation and Holistic Passivation Enables Efficient Two‑Terminal Perovskite/CuIn(Ga)Se_(2)Tandem Solar Cells

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Nano-Micro Letters 2025年第1期17卷 205-215页

作者： Cong Geng Kuanxiang Zhang Changhua Wang Chung Hsien Wu Jiwen Jiang Fei Long Liyuan Han Qifeng Han Yi‑Bing Cheng Yong Peng State Key Laboratory of Advanced Technology for Materials Synthesis and Processing Wuhan University of TechnologyWuhan 430070People’s Republic of China Triumph Photovoltaic Materials Co. Ltd.No.1001 Yannan AvenueHigh‑Tech Development DistrictBengbuAnhui 233000People’s Republic of China College of Materials Science and Engineering Guilin University of TechnologyGuilin 541004People’s Republic of China State Key Laboratory of Metal Matrix Composites Shanghai Jiao Tong UniversityShanghai 200240People’s Republic of China

Two-terminal(2-T)perovskite(PVK)/CuIn(Ga)Se_(2)(CIGS)tandem solar cells(TSCs)have been considered as an ideal tandem cell because of their best bandgap matching regarding to Shockley–Queisser(S–Q)***,the nature of the irregular rough morphology of commercial CIGS prevents people from improving tandem device *** this paper,D-homoserine lactone hydrochloride is proven to improve coverage of PVK materials on irregular rough CIGS surfaces and also passivate bulk defects by modulating the growth of PVK *** addition,the minority carriers near the PVK/C60 interface and the incompletely passivated trap states caused interface recombination.A surface reconstruction with 2-thiopheneethylammonium iodide and N,N-dimethylformamide assisted passivates the defect sites located at the surface and grain ***,LiF is used to create this field effect,repelling hole carriers away from the PVK and C60 interface and thus reducing *** a result,a 2-T PVK/CIGS tandem yielded a power conversion efficiency of 24.6%(0.16 cm^(2)),one of the highest results for 2-T PVK/CIGS TSCs to our *** validation underscores the potential of our methodology in achieving superior performance in PVK/CIGS tandem solar cells.

关键词： PVK/CIGS TSCs Irregular rough surfaces Modulating the growth PVK/C60 interface recombination

Transmissive All-Dielectric Metasurfaces for Reconstructing Terahertz Holographic Images Via Polarization-Multiplexing And Polarization-Decoupling

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SSRN 2023年

作者： He, Xunjun Zhong, Zhaoyu Zhang, Ying Jiang, Jiuxing Yao, Yongtao Yang, Yuqiang School of Electrical and Electronic Engineering Harbin University of Science and Technology Harbin150080 China College of Science Harbin University of Science and Technology Heilongjiang150080 China National key laboratory of Science and technology on advanced composites in special environments Harbin Institute of Technology Harbin150080 China School of Electronic and Information Engineering Guangdong Ocean University Zhanjiang524088 China

Recently, the multifunctional terahertz metasurface holography (meta-holography) has garnered significant attention and sparked wide discussions due to its capacity for carrying a large amount of information. However, traditional multifunctional meta-holographies, achieved by integrating metasurfaces with active materials or MEMS technology, have exhibited distinct shortcomings due to the intrinsic properties of active materials, such as slow response, complex structure, or low reliability. Herein, a transmissive anisotropic metasurface platform, composed of all-dielectric meta-atoms including three components: elliptical silicon pillars (Si-pillar), circular Si-pillars, and a quartz substrate sandwiched between them, is proposed. This platform enables the implementation of dual-channel holographic images by utilizing linear polarization (LP) multiplexing and circular polarization (CP) decoupling. As proof of concept, two transmissive anisotropic metasurfaces (MS-1 and MS-2) are desiged. When illuminated with two orthogonal LP-polarization waves, the MS-1 displays holographic images of the letters "X" and "Y" in their corresponding co-polarized channels by switching the LP-polarized direction. Additionally, under left-circularly polarized (LCP) incidence on MS-2, two holographic images with different patterns ("L" and "R") are reconstructed in the co-polarized channel and cross-polarized channel respectively. Therefore, these polarization-multiplexed or polarization-decoupled metasurfaces exhibit considerable potential for applications in multifunctional integration and high information capacity. © 2023, The Authors. All rights reserved.

关键词： Circular polarization